Distributed midplane for computer system

ABSTRACT

A computer system including a frame, components and a pair of stacked controllers. The system also includes a plurality of midplanes positioned between the components and the controllers where each midplane includes a component edge and a controller edge, a first midplane connector coupled to the component edge and a second midplane connector coupled to the controller edge, where the first midplane connector is coupled to one of the component connectors and the second midplane connector is coupled to one of the controller connectors so that the midplanes are vertically oriented in parallel so as to define spaces therebetween. In one embodiment, the computer system is a data storage system, the components are storage drives and the controllers are storage controllers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of application Ser. No.17/094,936, titled, Distributed Midplane For Data Storage SystemEnclosures, filed Nov. 11, 2020.

BACKGROUND Field

This disclosure relates generally to a computer system and, moreparticularly, to a computer system that includes a plurality of spacedapart midplanes that each provide an electrical connection between acomponent and a pair of controllers, where the midplanes are distributedto allow increased airflow through the system.

Discussion of the Related Art

A typical 2U data storage system includes 24 storage drives, such ashard drives or flash drives, positioned at a front of the systemenclosure and two stacked storage controllers and power supply units(PSUs) positioned at the rear of the enclosure. Likewise, a typical 4Udata storage system includes 48 storage drives stacked in two rows of 24storage drives positioned at a front of the system enclosure and twostacked storage controllers and PSUs positioned at the rear of theenclosure. A printed circuit board assembly (PCBA) midplane ispositioned between the storage drives and the storage controllers andprovides an interconnection interface between the drives and thecontrollers for transmitting signals therebetween, where the midplaneincludes front side connectors that interface with the drives and rearside connectors that interface with the storage controllers. Thisconfiguration allows both of the controllers to access the data storedon all of the drives and provide the data through input/output cards tocertain servers and computing systems, where the controllers providesystem redundancy. Known midplanes can be very complex often includingtwelve or more layers providing numerous signal paths for connecting thedrives to the storage controllers.

As the industry moves from PCIe Gen 4 (16GT/s) to PCIe Gen 5 (32GT/s)protocols and higher, signal loss becomes worse and un-acceptable due tolong PCB trace on a known midplane, ultra-low loss PCB materials. Aspecific higher speed connector may be used to compensate for partialsignal loss and an extra re-timer may be added in order to meet signalquality requirements, but these solutions will significantly increaseproduct cost. In addition, the new generation drives and processorsinside the storage controller will consume more and more power, andthus, there will be a challenge for providing adequate venting forcooling of the storage controllers when employing known midplanesbecause these midplanes block airflow and reduce thermal performance.

SUMMARY

The following discussion discloses and describes a computer systemincluding a frame, a plurality of components positioned along a row at afront of the frame where each component includes a component connector,and a pair of stacked controllers positioned at a rear of the framewhere each controller includes a controller connector for eachcomponent. The system also includes a plurality of midplanes positionedbetween the components and the controllers where each midplane includesa component edge and a controller edge, a first midplane connectorcoupled to the component edge and a second midplane connector coupled tothe controller edge, and where the first midplane connector is coupledto one of the component connectors and the second midplane connector iscoupled to one of the controller connectors so that the midplanes arevertically oriented in parallel so as to define spaces therebetween. Inone embodiment, the computer system is a data storage system, thecomponents are storage drives and the controllers are storagecontrollers.

Additional features of the disclosure will become apparent from thefollowing description and appended claims, taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear isometric view of a known 2U data storage systemincluding a midplane that provides an electrical connection betweenstorage drives and storage controllers;

FIG. 2 is a front isometric view of the midplane removed from the systemshown in FIG. 1 ;

FIG. 3 is a rear isometric view of the midplane removed from the systemshown in FIG. 1 ;

FIG. 4 is a top view of a simplified illustration of a 4U data storagesystem including a plurality of distributed midplanes each connectingtwo storage drives to two system controllers;

FIG. 5 is a side view of the data storage system shown in FIG. 4 showingone of the midplanes being connected to two drives and the twocontrollers;

FIG. 6 is a side view of one of the midplanes separated from the datastorage system shown in FIG. 4 and illustrating signal trace linesbetween the drive connectors and the controller connectors;

FIG. 7 is a side view of a data storage system showing a midplane beingconnected to one storage drive and two controllers;

FIG. 8 is a side view of the midplane separated from the data storagesystem shown in FIG. 7 and illustrating signal trace lines between thedrive connectors and the controller connectors.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The following discussion of the embodiments of the disclosure directedto a computer system including a plurality of distributed midplanes eachconnecting one or two components to two controllers is merely exemplaryin nature, and is in no way intended to limit the disclosure or itsapplications or uses.

FIG. 1 is an isometric view of a known 2U data storage system 10including a frame 12, where an outer chassis of the system 10 has beenremoved to expose the components therein. The storage system 10 isintended to represent any suitable data storage system consistent withthe discussion herein and operates using any suitable protocol, such asperipheral component interconnect (PCI) express (PCIe), serial attachedSCSI (SAS), open coherent accelerator processor interface (OpenCAPI),Gen-Z, cache coherent interconnect for accelerators (CCIX), and computeexpress link (CXL). The system 10 includes a plurality of alignedstorage drives 14, for example, a row of twenty-four U2 drives, providedat a front of the system 10. The system 10 also includes a pair ofstacked storage controllers 16 and 18 positioned at a rear of the system10 and being operable to store and extract data among and between thedrives 14, as is well known by those skilled in the art. The system 10further includes a pair of PSUs 20 and 22 positioned adjacent to thecontrollers 16 and 18 providing power for the system 10 and a number offans 24 and heat sinks 26 for cooling purposes.

The system 10 also includes a midplane 30 positioned between the drives14 and the controllers 16 and 18 and providing electrical connectionstherebetween in a known manner, where the midplane 30 includes a PCBA 32having electrical traces to send signals among and between the drives 14and the storage controllers 16 and 18. FIG. 2 is a front isometric viewof the midplane 30 separated from the system 10 and showing a number ofdrive connectors 34 for connecting the drives 14 to the midplane 30.FIG. 3 is a rear isometric view of the midplane 30 separated from thesystem 10 and showing a number of controller connectors 36 forconnecting the storage controllers 16 and 18 to the midplane 30. Aspecial configuration of slots 38 and other openings extend through thePCBA 32 to allow airflow through the midplane 30 for cooling purposes. APSU connector 28 provides connection to the PSUs 20 and 22.

The electrical traces on the PCBA 32 provide signal paths between theconnectors 34 and 36. It is often necessary to route the traces aroundthe slots 38, which increases their length. Thus, as discussed above,the electrical traces in the midplane 30 and the know configuration ofthe slots 38 are often not conducive for the higher signal speeds andcooling requirements that are being developed in the art. For example,if greater cooling is required, the slots 38 may need to be larger,which likely will increase the length of the traces. Further, some ofthe slots 38 often need to be larger than other of the slots 38 forcooling purposes. Because of this, some of the controller connectors 36are electrically coupled to several of the drive connectors 34, whichalso requires increased trace length.

As will be discussed in detail below, this disclosure proposes replacingthe single piece midplane 30 with a plurality of spaced apartdistributed midplanes that allow for shorter signal traces between theconnectors that connect to the drives 14 and the connectors that connectto the storage controllers 16 and 18 and allow for the flow of airbetween the midplanes and establish redundant communications pathsbetween them. The traces on the distributed midplanes can be very shortto improve signal quality. In addition, the distributed midplanes reducethe total product cost compared to a traditional single piece midplanebecause they use a standard card edge connector that is low cost insteadof a pair of ultra-high-speed backplane connectors between the midplaneand the storage controller, have less PCB manufacturing cost due to lesscomplexity of the small midplane, have lower cost PCB raw material andless layer counts and eliminates the need for re-timers.

FIG. 4 is a top view and FIG. 5 is a side view of a simplifiedillustration of a data storage system 40 of the type shown in FIG. 1 .

The system 40 includes two stacked rows 42 and 44 of twenty-four storagedrives 46, for example, E3 drives in a 4U data storage system or E1drives in a 2U data storage system, each provided at a front of thesystem 10. The system 40 also includes a pair of stacked storagecontrollers 50 and 52 positioned at a rear of the system 40 and beingoperable to control data flow among and between the drives 46. Thesystem 40 further includes a pair of PSUs 54 and 56 positioned adjacentto the controllers 50 and 52 and providing power for the system 40,where an input/output (I/O) area 58 is provided between the PSUs 54 and56. The system 40 also includes twenty-four midplanes 60 distributed andspaced apart to provide spaces 62 therebetween. The system 40 furtherincludes a number of fans 64 that provide airflow between the midplanes60.

Each midplane 60 includes a connector 70 that is coupled to a connector72 in one of the drives 46 in the top row 42 and a connector 76 that iscoupled to a connector 74 in one of the drives 46 in the bottom row 44.Each midplane 60 also includes a connector 78 that is coupled to aconnector 80 in the top storage controller 50 and a connector 82 that iscoupled to a connector 84 in the bottom storage controller 52. FIG. 6 isa side view of one of the midplanes 60 separated from the system 40 andshowing a number of signal traces 86 formed in a PCB 88 between theconnectors 70, 76, 78 and 82. Diodes 88 control the flow of power fromthe controllers 50 and 52 to the drives 46. In one non-limitingembodiment, the connectors 72, 74, 78 and 82 are PCB golden fingers.

FIG. 7 is a side view of a 2U data storage system 90 similar to thesystem 40, where there is only a single row of the drives 46 and wherelike elements are defined by the same reference number. The system 90includes modified distributed midplanes 92 where the connector 76 hasbeen removed. FIG. 8 is a side view of one of the midplanes 92 separatedfrom the system 90 and showing a number of signal traces 94 formed in aPCB 96 between the connectors 70, 78 and 82.

The foregoing discussion discloses and describes merely exemplaryembodiments of the present disclosure. One skilled in the art willreadily recognize from such discussion and from the accompanyingdrawings and claims that various changes, modifications and variationscan be made therein without departing from the spirit and scope of thedisclosure as defined in the following claims.

What is claimed is:
 1. A system comprising: a frame; a plurality ofcomponents positioned along a row at one end of the frame where eachcomponent includes a component connector; at least one controllerpositioned at an opposite end of the frame where the at least onecontroller includes a controller connector for each component; and aplurality of midplanes positioned between the components and the atleast one controller where each midplane includes a component edge and acontroller edge, each midplane further including a first midplaneconnector coupled to the component edge and a second midplane connectorcoupled to the controller edge, wherein the first midplane connector iscoupled to one of the component connectors and the second midplaneconnector is coupled to one of the controller connectors so that themidplanes are vertically oriented in parallel so as to define spacestherebetween.
 2. The system according to claim 1 wherein the at leastone controller is a pair of controllers and wherein each midplaneincludes a third midplane connector coupled to the controller edge andanother one of the controller connectors.
 3. The system according toclaim 1 wherein each midplane further includes a third midplaneconnector coupled to the component edge and being connected to one ofthe component connectors.
 4. The system according to claim 1 wherein thesystem is a 2U data control system, the at least one controller is apair of stacked controllers, the plurality of components is 24components and the plurality of midplanes is 24 midplanes.
 5. The systemaccording to claim 1 wherein the system is a 2U data control system, theat least one controller is a pair of stacked controllers, the pluralityof components is 48 components provided in two stacked rows of 24components and the plurality of midplanes is 24 midplanes.
 6. The systemaccording to claim 1 wherein the system is a 4U data control system, theat least one controller is a pair of stacked controllers, the pluralityof components is 48 components provided in two stacked rows of 24components and the plurality of midplanes is 24 midplanes.
 7. The systemaccording to claim 1 wherein the at least one controller operates usingPCI express (PCIe), serial attached SCSI (SAS), open coherentaccelerator processor interface (OpenCAPI), Gen-Z, cache coherentinterconnect for accelerators (CCIX) or compute express link (CXL)protocol.
 8. The system according to claim 1 wherein the system is adata storage system, the components are storage drives and thecontrollers are storage controllers.
 9. A system comprising: a frame;twenty-four components positioned along a row at a front of the framewhere each component includes a component connector; a pair of stackedcontrollers positioned at a rear of the frame where each controllerincludes a controller connector for each component; and twenty-fourmidplanes positioned between the components and the controllers whereeach midplane includes a printed circuit board (PCB) having opposingside surfaces, a front edge, a rear edge and a plurality of electricaltraces, each midplane further including a first midplane connectorcoupled to the front edge, a second midplane connector coupled to therear edge and a third midplane connector coupled to the rear edge,wherein the first midplane connector is coupled to one of the componentconnectors and some of the electrical traces, the second midplaneconnector is coupled to one of the controller connectors and some of theelectrical traces and the third midplane connector is coupled to anotherone of the controller connectors and some of the electrical traces sothat the midplanes are vertically oriented in parallel so as to definespaces therebetween relative to a front to rear direction of the frame.10. The system according to claim 9 wherein the controllers operateusing PCI express (PCIe), serial attached SCSI (SAS), open coherentaccelerator processor interface (OpenCAPI), Gen-Z, cache coherentinterconnect for accelerators (CCIX) or compute express link (CXL)protocol.
 11. The system according to claim 9 wherein the system is adata storage system, the components are storage drives and thecontrollers are storage controller.
 12. A system comprising: a frame;forty-eight components positioned as two stacked rows of twenty-fourcomponents at a front of the frame where each component includes acomponent connector; a pair of stacked controllers positioned at a rearof the frame where each controller includes a controller connector foreach drive; and twenty-four midplanes positioned between the componentsand the controllers where each midplane includes a printed circuit board(PCB) having opposing side surfaces, a front edge, a rear edge and aplurality of electrical traces, each midplane further including a firstmidplane connector coupled to the front edge, a second midplaneconnector coupled to the front edge, a third midplane connector coupledto the rear edge and a fourth midplane connector coupled to the rearedge, wherein the first midplane connector is coupled to one of thedrive connectors of a drive in one row and some of the electricaltraces, the second midplane connector is coupled to one of the componentconnectors in the other row and some of the electrical traces, the thirdmidplane connector is coupled to one of the controller connectors andsome of the electrical traces and the fourth midplane connector iscoupled to another one of the controller connectors and some of theelectrical traces so that the midplanes are vertically oriented inparallel so as to define spaces therebetween relative to a front to reardirection of the frame.
 13. The system according to claim 12 wherein thesystem is a 2U system.
 14. The system according to claim 12 wherein thesystem is a 4U system.
 15. The system according to claim 12 wherein thecontrollers operate using PCI express (PCIe), serial attached SCSI(SAS), open coherent accelerator processor interface (OpenCAPI), Gen-Z,cache coherent interconnect for accelerators (CCIX) or compute expresslink (CXL) protocol.
 16. The system according to claim 12 wherein thesystem is a data storage system, the components are storage drives andthe controllers are storage controllers.